Crop protection compositions can in principle be formulated in different ways, the properties of the active ingredients and the nature of the formulation possibly posing problems in terms of the ease of preparation, stability, ease of application, and activity of the formulations. Moreover, for reasons of economics and ecology, certain formulations are more advantageous than others.
Generally there is a need for highly concentrated formulations of active ingredients, since such formulations are associated with a number of advantages. For example, the cost and complexity of packaging required is less than for low-concentration formulations. Correspondingly there is a resultant reduction in the cost and complexity of production, transport, and storage, and additionally the operations of preparing the spray liquids that are used in agriculture, for example, are simplified as a result of the handling of low-volume containers of crop protection compositions, such as during the operations of dispensing and of stir-mixing, for example.
Liquid formulations have the advantage over powder formulations that upon the reconstitution of a spray liquid, typically by adding water, they do not produce dust. Preferred liquid formulations, at they are concentrated, are suspension concentrates. A suspension concentrate is defined as a suspension of solid particulate active ingredients in a liquid intended for dilution with water before use. In spite of their ease of use, they are not as concentrated as e.g. powders. The amount of liquid phase comprised in the formulation, such oil or water, is typically more than half.
Product development has targeted to obtain fungicidal suspension concentrates comprising as much active ingredient as possible. However, the degree of concentration is limited by the requirement to obtain a stable product, that is wherein the solid particulates do not settle and which can be stored over extended periods of time.
Efforts have concentrated on the reduction of the particle size of the active ingredient. An increased surface area obtained thereby is often correlated with a higher chemical activity. Formulators have introduced surfactants into suspension concentrates to improve wetting properties to keep the active ingredient particles dispersed in the liquid phase.
Dodecylguanidine acetate, known as dodine, is a fungicide recommended for the control of a number of major fungal diseases of crops. Dodine is currently formulated as wettable powders, suspension concentrates and wettable granules. It is a slightly yellow fine powder with low solubility in water, in particular 0.63 g/l at 25° C., and organic solvents. It is used against almond scab; apple and pear scab; banana sigatoka; cherry leaf spot; olive leaf spot; peach bacterial spot and leaf curl; peanut early and late leaf spot; pecan scab, liver spot, brown and downy leaf spot, leaf blotch and downy mildew; and walnut anthracnose.
In spite of the importance of these active ingredients, developments in the area of suspension concentrates comprising dodecylguanidine, or a salt, or ester thereof, have been limited. Stable suspension concentrates of dodecylguanidine acetate typically comprise 400 g active ingredient per liter. This is disadvantageous as transport of products is costly. This is certainly the case where most of the product is water. In order to reduce the environmental impact of such formulation it would be advantageous to be able to produce formulations that are much more concentrated. It is also of interest to have formulations that have an improved toxicological profile, yet are sufficiently effective against the targeted pest.
US 2008/274154 teaches that suspension concentrates containing acrylic graft copolymer surfactant and an ionic alkoxylated polyarylphenol phosphate ester surfactant are stable over time at high concentrations of active materials.
US 2009/325808 describes highly concentrated suspension of slightly water soluble pesticides that are protected from Ostwald ripening by the use of polymeric surfactants. Also EP 0 007 731 discloses that highly concentrated suspensions of agrochemical active ingredients may be obtained using polymeric surfactants.
WO 2009/082939 describes that very concentrated suspensions of fungicides may be obtained by stabilizing an agrochemical active ingredient with one non-ionic dispersing agent and one anionic dispersing agent. Dodine is one of the fungicides that can be formulated in this way.
The above mentioned disclosures relate to anionic surfactants. This type of surfactant is not compatible with dodine.
EP 0 388 239 discloses the use of so-called structured surfactants for the preparation of highly concentrated suspensions of agrochemical or biocidal active ingredients.
None of these disclosures describes suspension concentrates of dodecylguanidine, or its salts, having a concentration above 40%.
There remains a need in the art for improved fungicidal suspension concentrates comprising dodecyl guanidine, or a salt, or ester thereof.
The present invention aims to resolve at least some of the problems mentioned above. The invention thereto aims to provide a more concentrated formulation than could be achieved thus far. The fungicidal suspension concentrate should be stable upon prolonged periods of storage. It should be economical. The ecological profile should be considered. The efficacy for the treatment of fungicidal diseases on agricultural crops should be maintained or improved.